1. Field of the Invention
This invention relates to artificial fireplace logs which provide a colored flame shortly after ignition. A preferred embodiment provides, in addition to the colored flame, a realistic crackling sound similar to that of a wood burning fire.
2. Description of the Prior Art
Fireplaces have been used in homes over the years for a variety of reasons. Originally, the basic functions of fireplaces were for heating and cooking whereas, at present, they are used primarily to provide a visual type enjoyment which one derives from watching burning logs. The burning of logs produces many aesthetic effects, such as pleasant aromas, colored flames, crackling noises, among others. The type and condition of the wood used will determine to a major part the extent of these effects but, in general, all burning wood produces these aesthetic effects to some degree.
While the burning of wood logs in home fireplaces has been the predominant method for providing this aesthetic pleasure over the years, there has been an increasing demand for artificial fireplace logs. These logs are easier to purchase and store, and since their heat output (including flame heat) is much greater per pound than for an ordinary wood log, a pleasing, lasting fire may be made from only one log. Other advantages are that they are much safer and easier to kindle than wood logs and require little or no maintenance during their burning.
These logs are manufactured to burn for about 2-3 hours, and are usually made of a carrier material, such as sawdust, and a flammable material, e.g., wax, which are mixed together are then extruded under pressure to form the log. The logs are usually packaged in a combustible wrapper (e.g., paper) and are easily set on fire by placing the wrapped log on a fireplace grate and igniting the wrapper with a match. The wrapper may have an inner barrier, e.g., of polyethylene film, to protect against migration of the wax into the paper. Paper or other similar combustible material may be put in the fireplace with the log if the log is not so wrapped. Once ignited, the log will continue to burn with a flame until the wax is consumed.
Unfortunately, however, artificial logs do not truly simulate the asethetic effects produced by a wood burning log. The logs, for the most part, merely provide a flaming mass which has none of the actual characteristics of a wood burning fire. While attempts have been made to provide an artificial log product which would truly simulate a wood burning fire, these attempts have fallen short of their goal. The major thrust in this regard has been to add chemicals to the log to impart an attractive color, or colors, to the flames. Thus, for example, U.S. Pat. Nos. 3,297,419, 3,637,355, 3,660,055, 3,726,651 and 3,843,366 describe the constituents of conventional artificial fireplace logs and other adjuvants therein and methods of making the logs. In U.S. Pat. No. 3,637,355 it is indicated that when the known metallic flame coloring agents are used in such logs it is necessary to use another additive, namely a chlorinated vinyl polymer, in order to provide a colored flame almost immediately upon ignition. In applicant's experience the use of conventional metallic coloring agents, such as copper sulfate, does not itself give a colored flame until the log has been burning for a relatively long time such as about 1/2 hour (which may constitute more than 15% of the total burning time). The same U.S. Pat. No. 3,637,355 also teaches that the incorporation of such known flame colorants as potassium nitrate and strontium nitrate gives undesirable rapid flaming, spitting and melting.
As far as applicant is aware, none of the prior art artificial fireplace log products provide a combination of an almost immediate flame color and a crackling sound similar to that of a wood burning fire upon ignition, and until the flammable material of the log is essentially consumed.